Videos are increasingly being displayed on handheld displays. However, in certain cases it has been found that videos watched on the contemporary handheld displays should not ordinarily exceed the length of 15-20 minutes to avoid uncomfortable experience by the user. This is at least partly attributable to the small size of handheld displays.
Projection is one of the methods for escaping the bounds of small screens in mobile devices. However, the usability and image quality for projection systems have thus far been such that mobile usage has not been attractive. Also the projection surface (i.e. projection screen) in the mobile environment varies a lot from ideal white screen as you may not have such an ideal white screen on which to project. For example, the projection surface could be textured, colourful, and rough in the case that a user is projecting the image onto the back of an airplane seat. These variations can lead to distortions of a projected image as perceived by a user.
Typically a mobile projector needs good flat surface on which to project the image. Also for a good quality projection, the surface of the projection should be white in colour, and should not have any other colours or patterns. However, such suitable mobile projectors are rarely available.
Even if the projection surface might be flat and single white coloured, the projection set-up might not allow the direct projection of the image onto the screen. This would make the projected image appear to be distorted image on the screen.
Existing projection screens can be rolled into a comparatively small configuration for storing or transport. However, such rolled projection screens are not readily user portable.
One or more aspects and embodiments of the present invention address one or more of the above-mentioned problems.
The image quality of a projected image, particularly in mobile use can be affected by one or more of the following factors:                i) If the image is projected on a moving surface the user perceived image looks to be out-of-focus;        ii) If the image is projected on a solid surface, but projector is moving, the perceived image looks to be out-of-focus;        iii) If the image is projected on a solid surface, with a non-moving projector, but the optics are set incorrectly, the perceived image looks to be out-of-focus;        
One or more aspects and/or embodiments of the present invention relate to the provision of auto-focussing for mobile projectors in such environments.
Furthermore, particularly in mobile environments, the projection surface/screen could be e.g. textured, colourful, and rough, which causes distortions to perceived image. In such cases, the projected image quality can be affected. For example, if the image is projected on rough surface the perceived image looks distorted. If the image is projected on colourful surface the perceived colours may not be correct. If the image is projected on a textured surface, the perceived projected image looks distorted. Furthermore, if the image is projected on a dark surface the perceived projected image looks darker than if it were to be projected on a light surface.
One or more aspects and/or embodiments of the present invention relate to the provision of enhancing image quality, particularly in mobile projectors.
Relative movement between the projector and a projector screen can cause user-perceived distortions. This is particularly so for hand-held projectors and/or projector screens. Image stabilisation would be beneficial. Aspects and/or embodiments of the present invention relate to projected image stabilisation.
When a mobile projector is set-up in a new place of use, the user often needs to manually correct the projected image, for example with keystone correction (to correct for geometric distortions), and/or level the projector horizontally so that the projected image is not appear rotated. Aspects and/or embodiments of the present invention relate to correction of such user perceived distortion.